The present invention relates to an apparatus and method to reclaim abrasives used in water jet cutting mechanisms. More specifically, the present invention relates to an apparatus and method to remove the sludge from an abrasive water jet cutting tank and recycle the abrasives for later reuse.
Industrial cutting has long been accomplished with hydraulic jetting of abrasives against a work surface to condition or cut the surface. Surface conditioning of steel slabs, blooms, and billets has also been accomplished with abrasive water jetting. The abrasives used in these processes have historically been discarded after use or re-circulated in a slurry form to the jetting head because of the difficulty of recovery of clean, dried, and re-useable quantities of the abrasives. It is generally preferred to introduce the abrasives as a dry material at the mixing chamber of the jetting head to prevent excessive wear of the water jet head assembly.
Heretofore, attempts to recover abrasives from cutting operations required the operator to cease operations and then dump the contents of the sump used to collect the cutting slurry and settled particulate matter into settling barrels. After allowing the abrasives to settle, the water was dumped off the top of the settled grit and discarded. The bulk grit was thereafter shoveled into piles to dry. These labor intensive recovery methods were deemed uneconomic and the settled slurry consisting of abrasive particles, along with the cuttings from the process, was discarded without any attempt to recover the reusable grit. A variety of mechanical recovery mechanisms involving shaking tables or screens have been used to recover grit from the cutting slurry. These methods have proved useful, but still required extensive operator intervention to complete the recovery of reusable abrasives.
A preferred embodiment of the present invention relates to an abrasive recovery apparatus for use in conjunction with the slurry generated by water jet cutting or conditioning operations. The generated slurry is comprised of both non-recyclable fines and recyclable particles. The abrasive recovery apparatus comprises a self-clearing slurry intake system, a vibrating separator, and a fluidized bed dryer. The slurry intake system has one or more pumps which collect and move the slurry to the vibrating separator. The vibrating separator has a filter sized and shaped such that the non-recyclable fines in the slurry are separated from the recyclable particles in the slurry. A fluidized bed dryer has heating elements located to dry the recyclable particles.
Another preferred embodiment of the present invention provides an abrasive recovery apparatus for use in conjunction with the slurry generated by water jet cutting or conditioning operations. The slurry is comprised of non-recyclable fines and recyclable particles. The abrasive recovery apparatus comprises a slurry intake system, a vibrating separator, and a fluidized bed dryer. The slurry intake system is for distributing collected slurry. The slurry intake system has a sump pump, a nozzle-orifice arrangement, and a diaphragm pump. The sump pump provides continuous flow of dirty water through the nozzle and into the orifice connected to the low pressure side of the diaphragm pump. The diaphragm pump moves the slurry downstream from the sump to the vibrating separator and intermittently provides no flow through the orifice permitting the flow of dirty water from the sump pump to dislodge the abrasive grit agglomerated at the opening to the orifice.
In this preferred embodiment, the vibrating separator is downstream from the diaphragm pump for receiving the slurry, thereafter cleaning and separating the non-recyclable fines from the recyclable particles. The vibrating separator has a distributor, a shaker filter, a waste spout, a recycle spout, and a vibrator mounted on a shaker table. The distributor is a shallow pan for receiving and distributing the slurry to the shaker filter. The shaker filter has one or more screens to selectively remove non-recyclable fines from the slurry and pass them through the waste spout. The shaker filter further passes the recyclable particles through the recycle spout. To prevent the shaker filters from blinding or clogging, the shaker filter has a plurality of screen brushes which are free to move about both vertically and horizontally in the space between the filter screens to agitate the slurry and prevent clogging of the screens.
The fluidized bed dryer comprises a drying chamber, heating elements and a final product spout. Air is forced into the dryer from the plenum below the dryer through tuyeres and vents into the atmosphere. The drying chamber receives the recyclable particles from the recycle spout. Once received, the heating elements dry the recyclable particles which are passed out the final product spout which are then again selectively screened to separate recyclable grit from other undesired waste materials or other by-products of the cutting process.
Another preferred embodiment of the present invention provides a method for the recovery of dried abrasive from a water jetting operation. Slurry is received from an abrasive water jetting operation. The slurry is selectively pumped to a separator. Selected abrasive slurry particles are separated, washed and dried.
It is therefore a primary object of the present invention is to provide an automated mechanism and method of recovering cutting abrasives used in high-pressure water jet cutting mechanisms in a cleaned and dried condition.
It is a further object of the present invention is to provide a means for selectively grading and reclaiming the remaining fines or grit in a cutting slurry and diverting used or spent fines from the reusable materials for disposal.
It is another object of the present invention is to provide a environmentally safe drying operation which produces no toxic waste gases as a by-product of combustion through the use of electric heating elements.
It is yet another object of the present invention is to allow the use and recovery of a variety of abrasives having varying hardness as measured by the Mohs scale and a variety of particle sizes by easily changing the screen size of the selective washing and drying screen to segregate spent abrasives from reusable particles.
Another object of the present invention is to permit the recovery of precious and valuable metals from recyclable cutting grits thereby lowering the cost of recovery of such precious metals.
Other features, and the advantages, of the present invention will be made clear to those skilled in the art by the following detailed description of the preferred embodiments constructed in accordance with the teachings of the present invention.